“American Idol” is in its 12th season, which in TV years, is really, really old. There’s a hitch in its gait, a severe slouch in its ratings. Listen close enough and you can even hear some creaking in its bones.

But just when you think the show that Kelly Clarkson built has nothing new to offer, along comes an unexpected someone to drop a firecracker down its pants and provide a big blast of freshness and edge.

No, we’re not talking about Mariah Carey, the pampered pop princess who is proof that, when it comes to reality TV judges, you don’t always get what you pay for (see also: Britney Spears, “The X-Factor”).

We mean Nicki Minaj, the black Barbie doll with cotton-candy hair, a blinding smile and attitude to spare.

We never thought we’d say this, but Minaj is the best darn thing about “Idol” this season.

For the record, fellow rookie judge Keith Urban is also doing a fine job. He delivers the kind of crisp and insightful critiques that Steven Tyler might have offered had the Aerosmith frontman not spent so much of his “Idol” stint in a coma.

It’s Minaj, however, who is stealing the show. Those crazy-town hats and wigs, the random British accents, the puppy-dog eyes, the tendency to adorn contestants with silly nicknames (“Lady Bug,” “The Turbanator,” “Mushroom”), the snide side glances she casts Mariah’s way — they all make her an absolute hoot to watch.

But Minaj is much more than a nasally voiced cartoon character. She’s an intriguing multidimensional personality who, as a Rolling Stone writer pointed out, has been “hilarious, empathetic, slightly mean, sarcastic, witty, relatable, insightful and horny.”

As for that latter adjective, last week, she fawned over ousted contestant Chris Watson, telling him, “You are the prettiest man I’ve seen in my life. I want to marry your vibrato. I am obsessed with you.”

And speaking of obsession, when was the last time you heard an “Idol” judge tell a contestant that they want to “skin and wear” her? Um, OK, that’s a little creepy, but she meant it as a compliment.

What we really love about Minaj is the passion she’s brought to the panel. She’s engaged and attentive. She seems to be having loads of fun. And she gives good critiques.

That’s probably the biggest surprise. A rapper, Minaj may not boast the kind of vocal cred that Mariah and Urban do, but she has contributed plenty of thoughtful, helpful bits of analysis.

Minaj also brings a Simon Cowell-like toughness that has been glaringly absent from “Idol” since he left. She’s not afraid to go against her fellow panelists, or the crowd (“Get ready to boo again,” she said, tauntingly, to the live audience during a recent episode).

And, like Cowell, she doesn’t hesitate to give contestants a needed kick in the butt. When a tiny singer seemed to keep referring to his height for emotional effect, she warned him against starting a “pity party.” When another took the stage with a stressed-out, hangdog demeanor, she barked, “That’s such a turnoff. Just give us one minute of professionalism.”

As for that highly publicized feud with Carey, things fortunately have quieted down on that front, but there’s no question that Minaj has already landed a knockout punch in the battle for our attention. While delivering her reviews, Carey too often comes across as gun-shy, slightly clumsy and witless. It’s like she’s forgotten how to talk to “regular” people.

Things could change, of course. We’ve seen in the past how some judges will shine in the early rounds only to lose their luster during the live telecasts. And there’s always the possibility that we will tire of Minaj’s schtick.

But for right now, she’s the one we idolize.

WINTER BLUNDERLAND: In recent years, the broadcast networks have had to lower their expectations when it comes to TV ratings. But probably no one could have predicted just how abysmal the numbers would be for their midseason offerings.

We’re talking record-breaking lows here. When NBC unveiled “Do No Harm,” a medical drama, a few weeks ago, it posted the lowest in-season premiere rating for a scripted series in the history of the so-called Big Four networks. Shockingly, only 3.1 million viewers showed up for the show, which was axed after just two episodes.

ABC’s “Zero Hour” also tanked. The premiere of the occult adventure series starring “ER” vet Anthony Edwards, drew 6.3 million viewers, making it the least-watched scripted-series debut ever on ABC.

For comparison’s sake, “Last Resort,” a now-canceled ABC drama that aired in the same Thursday-night time slot earlier this season, drew 9 million viewers to its premiere.

And there’s more bad news. The CW’s suspense thriller “Cult” attracted only 940,000 viewers to its opener; ABC’s “Body of Proof” debuted to a series-low rating; NBC’s “Smash” has also hit a series low this month. On and on it goes.

In the case of “Smash,” the numbers are particularly discouraging. The ambitious Broadway-themed drama underwent a significant makeover and signed up powerhouse vocalist Jennifer Hudson for a few episodes in the hopes of seizing more attention. Clearly, it hasn’t worked.

But still, they keep trying. Up next this weekend is the two-hour premiere of “Red Widow” (9 p.m. Sunday, ABC), a drama set in San Francisco and Marin about a single mother (Radha Mitchell) who is drawn into the world of organized crime after her husband is murdered. ABC, clearly in need of a hit, has invested plenty of promotional oomph into the show.

All we can say is: Don’t get your hopes up.

EYE ON YOUTH VIOLENCE: News anchor Anderson Cooper turns his attention to an important and timely social issue in “The Bully Effect: An Anderson Cooper Special” (10 p.m. Thursday, CNN). It’s a program that chronicles the journeys of a bullied child, a grieving parent, a victim of violence, and a filmmaker turned activist (Lee Hirsch; “Bully”). Each has become a foot soldier in the battle against bullying, inspiring a grass-roots movement that has helped spark sweeping changes from school policies to state laws to federal legislation.

The special is presented in partnership with Cartoon Network’s “Stop Bullying: Speak Up” campaign. It is scheduled to re-air at 8 p.m. on March 3 and 9.